Air-brake



(Np M06131!) W. W. HANSCOM.

AIR BRAKE.

FIG 5.

Patented Aug. 30, 1887.

UNITED STATES PATENT OFFICE,

WILLIAM WALLACE HANSCOM, OF SAN FRANCISCO, CALIFORNIA.

AIR-BRAKE.

SPECIFICATION forming part of Letters Patent No. 369,057, dated August 30, 1887.

Applioationfiled October 8, 1886. Serial No. 215,745. (No model.)

To all whom, it may concern.-

Be it known that I, WILLIAM WALLACE HANSOOM, of the city and county of San Francisco, State of California, have invented an Improvement in Air-Brakes; and I hereby declare the following to be a full, clear, and exact description of thesame.

My invention relates to certain improvements in air-brakes, and has for its purpose the more efficient operation of compressed-air brakes on railway-trains, and more especially in that class known as straight air-brakes, in which the air is ordinarily first compressed by an air-pump or compressor and forced into a large reservoir, where it is stored for use as required, and from which it is sent along the train into the brake-cylinders when it is desired to apply the brakes.

In my invention I have connected the aircompressing cylinder directly with the trainpipe and dispensed entirely with the intermediate reservoir, so as to discharge the air di- Eectly from the air-pump into the brake-cylin- Referring to the accompanying drawings for a more complete explanation of my invention, Figure l is a side elevation showing a locomotive with tender, to illustrate my invention. Fig. 2 is a section of the valve F. Fig. 3 shows the brake-connections on a car.

It is well known that when a reservoir is employed a higher pressure of air must be maintained in the reservoir than is actually necessary for applying the brakes with the proper degree of force. The reason of this is that when the air is let out of the reservoir to fill the brake-cylinders its volume is increased and its pressure diminished to such an extent that more than double the necessary pressure has to be accumulated in this reservoir, especially where long trains are to be controlled, and unless this reservoir is made of very large size the pressure is so rapidly diminished in applying the brakes that it is often difficult to obtain the desired pressure when frequent stops have to be made, as in the case of local or suburban trains. This excessive pressure must be maintained, and it also requires a long time to compress the large quantity required to fill a reservoir of sufficient size for the pipes.

In my invention I dispense entirely with the reservoir, and discharge the air directly from the airpump into the brake-cylinders when the stop is required to be made or the brakes are to be applied. By this means I avoid the necessity of compressing the large quantity of air to at least double the necessary pressure, and thus reduce the labor of the pump, and can increase the proportion of the air-piston compared with the steam-piston of the compressor to a greater size than could be employed ordinarily.

A is the boiler of aloconiotive, andB is the air-cylinder of the compressing-pump, C be ing the steam-cylinder having the usual or any suitable valve-gear by which it is caused to reciprocate when steam is introduced, and thus actuate the pump-piston.

D is the pipe which conveys the air from the air-compressing cylinder to the engineers brake-valve E, and F is a safety or governor valve, which is loaded to just above the pressure necessary for operating the brakes, this valve intervening between the air-compressing cylinder and the engineers brakevalve before described.

G is thesteam-pipe connecting the boiler and the steam-cylinder of the air-compressor, and it is provided with the throttle-valve I, by

which steam may be admitted or cutoff, at the will of the engineer.

H is a pipe which extends from the engineers brake-valve downward beneath the foot board, and thence connects with pipes extending beneath the train and connecting with the various brake-cylinders, K, by which the brakes are applied to the wheels of the cars, the ordinary flexible couplings being employed to unite these pipes beneath the train.

In operating this apparatus the throttlevalve is opened so that the compressor will work and generate a pressure which will just raise the safety or governor valve F, and the compressed air will escape, the brake-valve being closed so that no air can pass into the train-pipe H. \Vhen the air pressure has been raised so that it will open the governor-valve,

the throttle-valve is partially closed, so that the compressor will move at a slow speed.

In operation, the object of the governor or safety valve is to allow the air compressor or pump to be worked at a slow speed under a regulated pressure, and to allow any excess of pressure to blow away. It is not intended that the pump shall be stopped when a fixed pressure is reached, but to be kept continually in motion. When the brake-valve is opened, this allows afree escape of air into the train-pipe and brake-cylinders, and the pump will then increase its speed.

The object in keeping the pump in motion at a slow speed when it is not required to apply the brakes is to keep the steam-cylinder free from the water of condensation, which is continually gathering, and would, if the pump were stopped, accumulate in the steam-cy1inder and fill it up, thus requiring some time to empty it, so that it would run at a slow speed when it is required to be run comparatively fast to regulate the pressure in the brake-cylinder.

If a governor-valve were used which would allow the steam to be shut 01? when a fixed pressure is reached, the pump would stop and would not be prepared for quick movement when required. This governor or safety valve is such a one as is commonly used for allowing an excess of air to escape when the required pressure is reached.

The pressure can be regulated by screwing down the nuts on top of the spring.

\Vhen the brakes are to be applied, the brakevalve D is opened and air is admitted to the traiu-pipe H, which allows a free passage for the air to the brake-cylinders, and the compressor will immediately commence running faster, until the pressure in the brake-cylinders increases to the point at which the governor-valve is loaded, the speed being gradually decreased as the pressure increases tlhroughout the train-pipe H and brake-cyliners.

rapidly, because, being pumped directly into the train-pipe and brake-cylinders,thcre is no This pressure can be increased veryv large reservoir to be replenished, and it may always be regulated to a nicety, so that the amount of pressure applied in the brake-cylinders may be just inside of that limit beyond which the wheels would be entirely prevented from turning, and which would cause them to be flattened in spots and ruined by sliding upon the rails. By this construction I am enabled to apply the brakes very rapidly, and the train can always be kept under easy control, on account of the direct connection between the air-compressing cylinder and the brake-cylinders and the fact that no large reservoir must be filled and pressure maintained in it.

In my invention the independent compressor is worked without reference to the speed of the train,and will operate as long as there is steam supplied in the boiler.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

Brake-cylinders within which the brakeactuating pistons are moved,air-pipes connecting said cylinders with the locomotive, in combination with an independent air-compressor attached to said locomotive, a steam-pipe and throttlevalve by which the supply of steam to the steam-cylinder is controlled, a pipe connecting the air-eompressor with the train-pipe and having a brakevalve situated therein, and a governor-valve connecting with this pipe intermediate between the brake-valve and the aircompressor, substantially as herein described.

In witness whereof I have hereunto set my hand.

WiLLIAill WALLACE HANSCOM.

XVitnesses:

C. D. Conn, J. H. BLOOD. 

